HI-05 is a deep-water site containing both conventional and chemical military munitions. Consistent with an internationally accepted practice at the time, DoD disposed excess, obsolete or unserviceable munitions, including chemical warfare material, in ocean waters off the U.S. prior to 1970, at which time DoD discontinued this practice. Congress effectively prohibited sea disposal of waste materials into the ocean in 1972. UH Mānoa is undertaking this research in partnership with the U.S. Army, Woods Hole Oceanographic Institution and Environet Inc., a local environmental consulting firm.

Assessing the ecological impact

This effort is a continuation of the Hawaiʻi Undersea Military Munitions Assessment (HUMMA) that used towed sidescan sonars, Hawaiʻi Undersea Research Laboratory submersibles and remotely operated vehicles to locate and assess the effects of the ocean environment on sea-disposed munitions and sea-disposed munitions on the ocean environment and those who use it. Four previous field programs imaged thousands of conventional munitions and over a hundred suspected chemical munitions. Additionally, these efforts collected sediment, water and biological samples within two meters of conventional and chemical munitions.

Analyses of sediment samples collected less than two meters from suspected chemical munitions indicated the presence of mustard agent and its degradation products at levels of less than five parts per million. Shrimp scavenging nearby and sea stars living directly on top of suspected chemical munitions exhibited no adverse impact from munitions constituents. The upcoming program will focus on these munitions to determine if there have been any changes in biota, sediment and water chemistry.

Encouraging open dialogue

“The Army believes this research will close additional knowledge gaps about the potential impact of sea disposed munitions on the ocean environment and those people that use it,” said Hershell Wolfe, deputy assistant secretary of the Army for Environment, Safety and Occupational Health. “The expected results will benefit not only the DoD, but the international community,”

“HUMMA has dramatically increased our understanding of what is happening at historical sea disposal sites,” stated Margo Edwards, UH principal investigator. “We have been sharing the methods developed and results discovered by UH at international meetings in support of an open dialogue for a global problem.”

In that spirit, the upcoming expedition will host observers from Australia who will gain direct experience with the approaches and tools used to investigate sea disposal in Hawaiian waters. These international partnerships support a primary goal of UH’s Hawaiʻi Innovation Initiative (HII)—broadly transitioning our research and knowledge to enhance global understanding.